class BaseForm(object):
    # 在此列表中的字段不处理
    base_class_exclude = []

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)

        for name, field in self.fields.items():
            if name in self.base_class_exclude:
                continue

            old_class = field.widget.attrs.get('class', "")
            field.widget.attrs['class'] = '{} form-control'.format(old_class)
            field.widget.attrs['placeholder'] = "请输入{}".format(field.label)
